It is known that an overexpression of plasminogen activator inhibitor-1 (PAI-1) inhibits the production of plasmin that decomposes fibrin thrombi and tissue proteins and brings a formation of thrombi (for example, refer to the Non-patent Document 2) by inhibiting the activation of plasminogen activator (for example, tissue-type plasminogen activator and urokinase-type plasminogen activator).
Furthermore, the overexpression of PAI-1 is observed in arteriosclerotic lesions, and is known to increase a risk of thrombotic diseases such as cardiac infarction, deep-vein thrombosis (DVT), disseminated intravascular coagulation (DIC) following sepsis and the like (refer to the Non-patent Document 1).
From these facts, compounds that inhibit PAI-1 activity or production are useful for the suppression of forming thrombus, and are expected to be useful drugs to diseases caused by the formation of thrombi such as thrombotic diseases, diseases involving thrombus formation and the like.
Furthermore, it is known that PAI-1 promotes precipitation and accumulation of extracellular matrix and is deeply involved in the development of tissue lesion featuring fibrosis and vascular wall sclerotic lesion. As an extracellular matrix accumulation in the airway of an asthma model mouse is reduced by a PAI-1 knockout (refer to the Non-patent Document 8), it is suggested that PAI-1 is directly involved in the fibrosis. Therefore, compounds that inhibit the activity or production of PAI-1 are useful for the inhibition of fibrosis of tissue, and are expected to be useful drugs to a diseases caused by the fibrosis of tissue.
Besides, PAI-1 is also secreted from mast cells (refer to the Non-patent Document 7), and it is reported that the blood level is high in an obesity model mouse, and is synthesized not only in the endothelial tissue and in the hepatic tissue, but also synthesized in the fatty tissue. Particularly in the visceral fat, PAI-1 synthesis amount is exponentially enhanced together with its deposition (refer to the Non-patent Document 3). Moreover, in the obesity model mouse where PAI-1 gene is knocked out, a decrease of weight and a lowering of blood glucose level and blood insulin level are reported (refer to the Non-patent Document 4), and it shows that PAI-1 has a possibility to aggravate various pathological conditions caused by the fat deposition. Therefore, compounds that inhibit the activity or the production of PAI-1 are useful for the inhibition of visceral fat deposition, and are expected to be useful drugs to diseases caused by the visceral fat deposition.
Furthermore, from the facts that PAI-1 inhibits an adhesion of cell and extracellular matrix by binding to a vitronectin which is a cell adhesion factor, a PAI-1 antibody inhibits a cancer metastasis in a cancer model (refer to the Non-patent Document 5), and the infiltration of cancer and an angiogenesis are inhibited when malignant keratinocytes are transplanted to the PAI-1 knockout mouse (refer to the Non-patent Document 6), compounds that inhibit the activity or the production of PAI-1 are useful for the inhibition of cell migration, cell metastasis, angiogenesis and the like, and are expected to have therapeutic effects to diseases caused by cell migration, cell metastasis, angiogenesis and the like.
Moreover, arterial lesions as an acute rejection and a chronic rejection after heart or kidney transplantation are considered to be caused by the development of tissue fibrosis, the formation of thrombi, and the proliferation and the remodeling of arterial endothelial cell. Since, in the heart transplantation experiment using mise (murine), when a compound having an inhibitory activity to PAI-1 is administered, a graft survival is significantly prolonged compared with the control group and the rate of serious intimal hypertrophy is reduced to one third (refer to the Patent Document 1), compounds that inhibit the activity or the production of PAI-1 are expected as a medicament to inhibit an acute rejection and an arterial lesion after transplantation, after heart or kidney transplantation or transplantation of other organs.
On the other hand, as plasmin which is activated by inhibiting PAI-1 is involved not only in the decomposition of thrombi, but also in the remodeling of tissue, the migration, metastasis and infiltration of cells, the ovulation and implantation, the activation of transforming growth factors which are cytostatic cytokines, and the activation of collagenase, compounds that inhibit the activity or the production of PAI-1 are useful for the inhibition of tissue remodeling, the proliferation, migration, infiltration, and metastasis of cells, angiogenesis and the like, and treatment effects are expected to diseases caused by cell proliferation, angiogenesis, and remodeling of tissues and the like.
In the past, examples of compounds having PAI-1 inhibition activity include, for example, the compounds disclosed in the Patent Documents 1 to 19 and the Non-patent Documents 9 to 11. On the other hand, some compounds have been reported (refer to the Patent Documents 20 to 22) as oxamic acid derivatives, however, it is not known whether they have PAI-1 inhibition activity.